For many years, the preferred method of harvesting forage crop material has been to cut it, permit it to dry to at least a limited extent, form it into windrows, and then form the windrows into separate rectangular bales tied by wire or twine. In more recent years, formation of the windrows into roll-type bales has become popular. Such roll bales are usually secured by spirally winding binder twine around the rolls to a suitable extent. One advantage of roll bales is that they may be stored in a field and the cylindrical nature thereof forms a natural means to shed water when rained upon, but at least the outermost portions of such roll bales becomes deteriorated if left exposed over a period of time.
To obviate the aforementioned deterioration of round roll bales, very recent proposals have come forth to protect such bales with covering material, such as plastic film. One example of such solution is the subject of prior U.S. Pat. No. 4,173,112 to Meiners, dated Nov. 6, 1979, in which a roll bale is wrapped in sheet plastic film as the bale is formed and then the covering plastic film is severed from a supply roll by a shaped blade having a V-shaped cutting edge. The end of the wrapped film is then glued to the roll or otherwise the roll may be left in a field and permit the weight of the roll to prevent unwrapping of the covering film from the roll bale.
The wrapping art also offers some suggestions as to how a large cylindrical object, such as a roll of paper may be wrapped with a paper sheet, such as proposed in prior U.S. Pat. No. 4,224,782, to Moflag, dated Sept. 30, 1980, but adaptation of the rather complex structure thereof to a baler for round bales appears to be cumbersome and complex.
A German published application, No. 2,705,101, filed Nov. 23, 1978, appears to suggest wrapping a roll bale of agricultural material with a strip of what seems to be plastic material of limited width wound spirally around a roll bale with the edges of the successive convolutions overlapping a limited extent by threading the supply roll transversely across the bale somewhat similarly to the wrapping of binder twine around such a bale, as mentioned above relative to roll balers of earlier years.